Cataracta P. Zamora-Tavares, O. Vargas & M. Martínez, gen. nov.

Type: — Cataracta microphysa (A. Gray) P. Zamora-Tavares, O. Vargas & M. Martínez.

Basionym:— Physalis microphysa A. Gray. Proc. Amer. Acad. Arts 21: 402. 1886.

Etymology:—The name Cataracta honors U.T. Waterfall, who extensively studied the genus Physalis .

Herbae erectae, circa 20–40 cm altae, radices perennes; foliis 12–20 mm longo et 10–23 mm lata crenato-repandis, floralibus 12 a 20 mm diameter; corolla ochroleuca maculis fusco-luteis, plano-rotata; calyce fructifero ovato tereti 9–12 mm longo et 8–12 mm lata, fructus non capsularis dehiscens, seminibus crassiusculis immarginatis favosorugulosis.

Erect perennial rhizomatous herb, branched from a woody base, 15 to 60 cm long, with a long and thin rhizome; the entire plant densely pubescent with simple eglandular and glandular multi-cellular trichomes of 0.2–1 mm long; leaves reniform to ovate or subhastate, 1.2–2.0 cm long and 1.0– 2.3 cm wide, margin entire or sinuous with one to three teeth; leaf trichomes more or less appressed, generally shorter than stem trichomes; petiole 0.5–1.2 cm long but the most basal ones up to 6 cm long; flowers solitary on pedicels of 2 to 5 mm long; floral calyx 4–6 mm wide at the base, lobes lanceolate to slightly acuminate, lobed from the middle to a third of their length; corolla rotated with five small lobed tips, 1.2–2.0 cm in diameter, whitish yellowish with yellow to greenish maculas composed by tiny dots at the base of the lobes, anthers ovate-oblong, yellow, 1–1.5 mm long, on glabrous filaments 2–3 mm long; fruiting calyx terete, ovate-oblong to campanulate, 9–12 mm long and 8–12 mm wide, lobes acuminate, 2–4 mm long, lobes sometimes reflexed; fruit dehiscent dry berry, pericarp dry that breaks into irregular portions exposing the seeds, 5 to 7 seeds per fruit; seeds reniform with reticulate dark brown testa, 2 mm in diameter.

Comparison: — Cataracta microphysa is a perennial herb (Fig. 3A) with a solitary axillary flower as in Physalis, but the rotate whitish-colored corollas with a slight yellow or greenish tinge resembling those of Chamaesaracha spp. and the corolla shape resembling those of Quincula (Fig 3B). The fruiting calyx is terete, ovate-oblong to campanulate, inflated like in Physalis, but differing in being open-flaring apically and the lobes of the calyx are rolled outward (Fig 3C). The fruit is not a fleshy, non-dehiscent berry as in Physalis, but is a dehiscent, dry berry with a thin, dry pericarp closer to the dry fruits of Chamaesaracha and Oryctes, with the unique feature of dehiscing along irregular lines (Figs. 3D–E). The seed testa is dark brown and faveolated-rugous, while seeds of Physalis and Chamaesaracha species do not have such ornamentation (Fig 3D). A full comparison of the five morphologically closely genera is shown in Table 1 and Figure 4.

Phenology: —This species flowers and fruits from May to October, with a peak in fruiting from September to October.

Distribution: —Endemic to Mexico; states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas (Fig. 5).

Habitat: —In xerophytic scrub and in transition with pine-oak forests.

Representative specimens examined. MEXICO. Chihuahua: Santa Eulalia Mts, C.G. Pringle 317 (MO, MEXU) ; Batopilas de Manuel Gómez Morín, E of La Bufa, on S side of Barranca de Batopilas, 3300 ft, 27–31 Oct 1973, R. Bye 5677 (MEXU) ; Coyame, 16 miles SW of Coyame along Hwy 16 in narrow alluvial arroyo in Chihuahua Desert Scrub, near 29°16’N, 105°16’W, 16 Sep 1972, J. Henrickson 7649 (ANSM, IEB, MEXU); Julimes, ca 31 (air) miles NW of Julimes in a SW facing canyon above Rancho El Recuerdo in Sierra de Carrasco (S. of Sierra de Chorreras), 4500 ft, 28°47’N, 105°09’W, 15 Sep 1973, J. Henrickson 12940 (MEXU) ; Camargo, Sierra de las Pampas west of Hacienda El Berrendo, 1600–1800 m, 27°20’N, 104°43’W, 25 Aug 1972, F. Chiang et al. 8829 (MEXU) . Coahuila: Cuatro Cienegas, 22 (air) miles WNW of Cuatro Cienegas, in lower Canyon de la Hacienda of limestone Sierra de la Madera, 2–3 miles from roads end, 5200 ft, 27°03’N, 102°25’W, 26 Sep 1973, J. Henrickson 13556 (MEXU) ; Cuatro Cienegas, 35 (air) km of Cuatro Cienegas, in the lower limestone Canyon de la Hacienda on northside of Sierra de la Madera, 4700 ft, 27°05’N, 102°25’W, 4 Aug 1973, J. Henrickson 11850 (ANSM, MEXU) ; Cuatro Cienegas, 28 (air) miles WNW of Cuatro Cienegas, on the N slope of the Sierra de la Madera, 7.5 (air) miles W of Rancho Cerro de la Madera, at base of Cañon Desiderio, in upper Cañon Posos, 1700–1800 m, 27°19’N, 102°30’W, 13 Aug 1976, J. Henrickson 15311 (MEXU) ; Tlahualilo de Zaragoza, 29 (air) miles NE of Tlahualilo on west-facing shale slope on the east side of Sierra de los Remedios, 3750 ft, 26°36’N, 103°05’W, 9 Aug 1973, J. Henrickson 12174b (MEXU) ; Ramos Arizpe, Valle de los Angeles, Sierra de la Paila, without collector data (ENCB) ; Arteaga, al norte del Ejido Chapultepec, Sierra La Laja, 2473 m, 25°15’24’N, 100°51’54”W, 14 Jul 2004, F.J. Encina 116 (ANSM) ; Arteaga, Puerto San Lorenzo, Cerro La Campana, Sierra Hermosa, 2460 m, 2 Aug 1979, L. Arce s.n. (ANSM) ; Arteaga, Sierra de la Madera in Cañada de la Hacienda, NW of Cuatro Cienegas, 1850 m, 27°04’N, 102°25’20” W, 15 May 1992, M.H. Mayfield 1395 (ANSM) . General Cepeda, km 20 de la brecha La Paz-La Casita, 300 m al S de La Casita rumbo al Tejocote, 2092 m, 25°11’40”N, 101°26’26”W, 10 Sep 2017, A. Castro et al. (CIIDIR) . Nuevo León: Aramberri, La Escondida-San Francisco, 1750 m, 26 Aug 1992, G.B. Hinton et al. 22355 (ANSM, IEB, MEXU) . Tamaulipas: Bustamante, 4.8 mi NW of Hwy 101 on road to Bustamante; W-facing, steep slope overlooking deep valley, 1670 m, 23°25’N, 99°40’W, 15 Jun 1987, G. Nesom et al. 5977 (MEXU, QMEX) .